HOW TO Isolate an object in an image
Allow object recognition
Open a duplicate of the image in Photos, Safari, Preview or Quick Look and wait a moment for object recognition to take place. In Preview, that’s marked when the ‘+’ sign is added to the Get Info button at the top.
Remove the background
In the Tools menu, select the Remove Background command. While that’s selected, the proposed outline of the cut out object will be highlighted for you to check the right object will be cut out. Action that command.
Convert to PNG format
You’ll then be prompted to convert the image to PNG format, so the removed background can be made transparent. Click on Convert for the image to be changed and automatically saved, overwriting the original file.